Freeze prevention, Chillers deltachill – Airedale DeltaChill FreeCool 110kW - 1080kW User Manual
Page 11
Chillers
DELTACHILL
™
Chillers
11
Installation, Commissioning and Maintenance Manual :7025232 12/ 2013
Freeze Prevention
Glycol is recommended when a supply water temperature of +5°C or below is required or
when static water can be exposed to freezing temperatures.
Glycol of an appropriate concentration
(1)
is used within the system to ensure
adequate protection. Please ensure that the concentration is capable of
protection at least 3°C lower than ambient.
Water / glycol solution is constantly circulated through all waterside pipework
and coils to avoid static water from freezing.
Ensure that pumps are started and running even during shut down periods,
when the ambient is within 3°C of the solution freeze point
(1)
(i.e. if the solution
freezes at 0°C, the pump must be operating at 3°C ambient).
Additional trace heating is provided for interconnecting pipework.
(1)
Referrer to your glycol supplier for details
For a given percentage of glycol in the system there are correction factors that need to
be applied, the following tables can be used as a guide.
Ethylene Glycol Nominal Correction Factors
Glycol in System / Freezing Point ºC
(1)
10% / -4°C
20% / -9°C
30% / -15°C
40% / -23°C
Cooling Duty
Catalogue Data x by:
0.98
0.97
0.95
0.93
Input Power
0.99
0.98
0.96
0.95
Water Flow
0.99
1.02
1.04
1.07
Pressure Drop
1.05
1.20
1.38
1.57
Propylene Glycol Nominal Correction Factors
Glycol in System / Freezing Point ºC
10% / -2°C
20% / -6°C
30% / -12°C
40% / -20°C
Cooling Duty
Catalogue Data x by:
0.97
0.95
0.91
0.88
Input Power
0.99
0.98
0.96
0.95
Water Flow
0.98
0.97
0.95
0.95
Pressure Drop
1.08
1.17
1.31
1.45
Example
DCC033DR-08BMH0
operating at 7/12, 35°C Ambient, 20% Ethylene Glycol, with AC
condenser fans.
Catalogue
Figure Multiplier
Corrected
Figure
Cooling kW
(refer to
Performance Data
– Capacity Data
)
326
x 0.97
20%
Ethylene
Glycol =
316.2 kW
Input kW
(refer to
Performance Data
– Capacity Data
)
105.6
x 0.98
103.5 kW
Flow l/s
calculated
(DX (Mechanical Cooling kW)
15.56 l/s
x 1.02
15.87 l/s
T x 4.19
Pressure Drop kPa
(refer to
Error! Reference source not found.
, Error!
Bookmark not defined.)
TBA kPa
x 1.20
TBA kPa